Pressure Argon Plasma Jet Research Articles

Characteristics and mechanism of moniliform plasma plume in atmospheric argon jet

Atmospheric pressure plasma jet can produce a kind of remote plasma plume in open air atmosphere. Different from the usual conical plasma plume found in the literature, a spatially periodical swelling plasma plume is generated in an atmospheric pressure argon plasma jet excited with a low-frequency biased sinusoidal voltage. By optical and electrical methods as well as optical emission spectroscopy, discharge characteristics and formation mechanism of the plasma plume with spatially periodical swells are studied. Experimental results show that length of the plasma plume increases with the increase of flow rate. Moreover, the plume initiates once in each negative half voltage cycle and it does not initiate in positive half voltage cycle. Through high-speed imaging, a negative streamer is found to propagate along argon flow for the swelling plasma plume. There is a strong discharge near the nozzle of the plasma jet, which initiates once per voltage half cycle and provides welling positions downstream with active species. These active species can significantly enhance the discharge and induce the formation of a swell. Furthermore, optical emission spectrum is used to investigate spatial distribution of excited electron temperature and averaged excited electron temperature as a function of gas flow rate. Finally, a qualitative explanation is given for the experimental results discussed above.

A Regularly Swelling Hollow Plume Generated in an Atmospheric Pressure Argon Plasma Jet Excited by a Positively Biased Sinusoidal Voltage

Far different from common plasma plumes, a regularly swelling hollow plume is observed in an argon plasma jet. The results indicate that the regularly swelling plume appears only at a low-frequency voltage (lower than 1 kHz) that is positively biased. Waveforms of applied voltage and light emissions reveal that there is a barrier discharge inside the nozzle, which initiates once every half voltage cycle. Outside the nozzle, it initiates once every positive half voltage cycle and never at the negative half cycle. By fast photography, it can be found that the positive discharge stems from the rod end of the powered electrode and bends down to hug the tube surface, which finally propagates to the outside as a cathode-directed streamer due to the charge overflow effect. The bifurcating streamer propagates along the periphery of the argon flow, which results in a hollow structure of the plasma plume. Due to abundant active species provided by the positive discharges inside the nozzle, the diameter of the plasma channel is comparatively larger in the swelling regions than in other regions, which induces the swells of the plume. Furthermore, the negative barrier discharge is diffuse, whose influence on the swells can be neglected. Finally, the contribution of active species generated upstream of the swells is verified by investigating the distance between two adjacent swells as a function of gas flow rate and driving frequency.

Detection of OH radicals in atmospheric-pressure plasma jet by evanescent-wave laser-induced fluorescence spectroscopy

This paper reports the signal and noise in the detection of OH radicals by evanescent-wave laser-induced fluorescence (EW-LIF) spectroscopy. We adopted this method to detect OH radicals, which were produced within an atmospheric-pressure argon plasma jet, in the vicinity of a quartz surface. The dominant noise was the stray laser light which could not be eliminated by using a monochromator and an interference filter. This was because the detection optics looked at the total reflection point of the laser beam in the EW-LIF spectroscopy. It was impossible to detect the LIF signal in the duration of the laser pulse because of the intense stray light. On the other hand, thanks to the slow decay of the LIF intensity, we succeeded in detecting the LIF signal after the laser pulse. The intensity ratio between the LIF signal originated from the bulk plasma and the one induced by EW near the surface was 5000–10000, which can be explained by the difference in the observation volumes. The proportionality between the LIF intensities from the bulk plasma and the surface vicinity, when changing the discharge conditions, suggests that the surface loss probability of OH on the quartz surface was not affected by these changes.

Physical Plasma Treatment of Eight Human Cancer Cell Lines Demarcates Upregulation of CD112 as a Common Immunomodulatory Response Element

Cold physical plasma has not only been suggested as novel anticancer but also an immunomodulatory agent. As demonstrated by the Nobel Prize for Medicine and Physiology 2018, immunotherapies are among the most promising strategies to battle cancer by harnessing the power of the immune system. To understand the immunomodulatory effects of cold physical plasma in more detail, we have treated eight human cancer cell lines with the atmospheric pressure argon plasma jet kINPen. Purposefully, noncytotoxic conditions were applied to decipher the genuine oxidative stress response delivered by plasma, and not signaling events associated with cell death. Viability testing confirmed the low toxicity of the chosen treatment regimen. Using multicolor flow cytometry, we have screened the viable cell portion of eight human cancer cell lines against 18 markers of immunomodulation that included both immunostimulatory and immunosuppressive cell surface molecules. From this 18 $\times $ 8 matrix data set, an increase greater than 1.5-fold change was observed for CD40 in three cell lines, CD271 in one cell line, and CD112 for all cell lines analyzed. We conclude that with kINPen-plasma-mediated oxidative stress at levels of low cytotoxicity, upregulation of CD112 is a common immunomodulatory response element observed among the eight human cancer cell lines investigated.

Uniformity improvement of plumes in an atmospheric pressure argon plasma jet array by electric field optimization

Atmospheric Pressure Plasma Jet (APPJ) array is a promising way for producing plasma to process large-scale uneven surface. In this paper, the uniformity of a one-dimensional (1D) Ar APPJ array (three tubes with needle-ring electrode structure) driven by a nanosecond pulse power source is optimized through varying the distance between the tip of middle HV electrode and outside electrode, d. The effects of parameters (gas flow rate and applied voltage) on the uniformity of jet array are also investigated. The voltage-current waveform, discharge optical image and ICCD photograph are measured to reveal the jet-to-jet interactions. The results show that when d = 0 mm, the middle tube plasma jet length is always shorter than outsides, while all jets are ignited with almost equal length at d = 2 mm and the middle tube plasma jet length is longer than outsides at d = 4 mm. Thus, the uniform atmospheric pressure plasma jet array is obtained by setting d = 2 mm. The unconformity of the plasma jet array length is mainly attributed to the number of transferred charge of primary discharge. The results reported in our study would be able to promote the application of uniform jet arrays for various applications.

Control of hydrogen peroxide production in plasma activated water by utilizing nitrification

In this study, ammonia (NH3) vapor was added to an atmospheric pressure argon plasma jet generated by a sinusoidal power supply (with an applied voltage of 4 kV and frequency of 35 kHz) and it was analyzed by electrical, optical, and chemical probe measurements. A total gas flow rate of 1200 sccm under 2% flow rate of either water or ammonia solution at concentrations up to 0.75% mixed with 98% argon feeding gas. The dissipated power of the plasma jet estimated by voltage-charge plots was found to decrease continuously with increase in ammonia concentrations at a fixed applied voltage. The optical emission spectra inside the quartz tube obtained for the NH3 mixed plasma indicated the presence of nitrogen emission lines which were absent in the water only mixed argon plasma. Colorimetric measurements of hydrogen peroxide (H2O2) and nitrite () in plasma activated water (PAW) were performed at different consumed energy varied by plasma exposure time. The H2O2 concentration decreased to 4 ppm from 14 ppm, while the concentration simultaneously increased to 6 ppm from 1 ppm as the ammonia concentrations increased to 0.75% from 0% throughout 2.07 × 103 joule energy consumption. We also analyzed the corresponding variation of pH values, in absence of ammonia, PAW leads to acidification but addition of small amount of ammonia in plasma is sufficient to make it alkaline. Additionally, we measured the hydroxyl (OH) radical density in gas and liquid phases by utilizing UV absorption spectroscopy and chemical probe method, respectively. OH radical density in both phases also decreased with the increase in the NH3 concentrations. Experimental results obtained from this experiment can be attributed to control H2O2 concentrations in the PAW via plasma-assisted nitrification.

Regularly-swelling plumes generated in atmospheric pressure argon plasma jet excited by a biased sinusoidal voltage

Far different from conical plumes, regularly-swelling plumes are generated in an atmospheric pressure argon plasma jet excited by a biased sinusoidal voltage at low frequency. Depending on the polarity of bias voltage, the plumes with periodic swells can be solid or hollow. Results indicate that discharge initiates once per voltage cycle, which appears in the negative and positive half cycles for the solid and hollow plumes, respectively. By fast photography, it is found that streamers are involved propagating downstream of the argon flow for the two plumes. Transversely, the streamer diffuses for the solid plume, while it propagates only in the flow periphery for the hollow plume. Due to a high field, intense discharges near the nozzle provide the following swell positions with active species, which can remarkably enhance the discharges there and induce the swells. This formation mechanism of periodic swells is verified through investigating the distance of two adjacent swells as a function of gas flow rate and driving frequency. Moreover, spatial distributions of excited electron temperature and streamer propagation velocity are qualitatively explained based on the mechanism.

Improvement of inverted structure organic solar cells by Ar plasma treatment on P3HT:PC61BM active layer

In polymer solar cells, contact between layers and morphology of the layer’s surfaces has great and critical effect on performance of the solar cell. In this research, we have modified P3HT:PCBM active layer surface morphology by mild plasma treatment using cold atmospheric pressure Argon plasma jet to fabricate the inverted structure polymer solar cell and have perused its influence by various powers. At first, without plasma treatment measured efficiency of 2.15% was obtained. At the maximum influence of the plasma treatment efficiency of 3.26% was achieved that its improvement was obvious until a certain plasma power. The morphology of active layer surface was observed by atomic force microscope and devices absorption spectrum before and after plasma treatment was measured by spectrophotometer. Characterization of the plasma-induced surface changes will be performed using ATR-FTIR spectroscopy. Maximum improvement of solar cell characters was obtained in the short circuit current that improves from 7.60 to 9.22 mA cm−2.

Decolorization effect and related mechanism of atmospheric pressure plasma jet on Eriochrome Black T.

In this study, Eriochrome Black T (EBT) in water was decolorized by means of argon atmospheric pressure plasma jet (APPJ), which showed great decolorization performance. The results showed that the relatively high decolorization rate (approximately 80%) was obtained after plasma treatment for 6 min. Changes to some reactive oxygen and nitrogen species (RONS) in the liquid phase were detected. The contents of peroxide, HO·, O2 -·, and NO· in the plasma-treated EBT solution were much less than those in the activated water. The roles of H2O2 and HO· in the decolorization of EBT solution were explored by evaluating the effects of their scavengers, and by exploring the direct effect of H2O2. The results indicated that reactive oxygen species (ROS), especially HO· and O2 -·, played significant roles in the decolorization of the EBT solution. Analysis of degradation by-products indicated that plasma discharge could destroy the azo bond first and gradually break the aromatic rings of EBT molecules into small molecular compounds.

Super-hydrophobic film deposition by an atmospheric-pressure plasma process and its anti-icing characteristics

In this work, the super-hydrophobic (SH) surface was prepared through chemical vapor deposition process by an argon atmospheric pressure plasma jet source with HMDSN (hexamethyldisilazane) as the polymerization precursor. Plasma synthesized organosilicon (SiOxCyHz) thin films with water contact angle over 160° and sliding angle below 5°, were able to be achieved. FTIR and XPS analysis indicates a large number of hydrocarbon compositions were polymerized in the thin films enduing the latter very-low surface free energy. SEM shows the SH films display micro-nanostructure and with high degree of averaged surface roughness 190 nm evaluated by AFM analysis. From experiments under controlled low-temperature and moisture conditions, the prepared SH surface exhibits good anti-icing effects. Significantly prolonging freezing time was achievable on the SH thin films for both static and sliding water droplets. This investigation demonstrates the anti-icing potentials of SH surface prepared through low-cost simple atmospheric-pressure plasma polymerization process.

Experimental investigation of sterilization efficacy of green nails symptom and gray nails using an argon-based round atmospheric-pressure plasma jet

In recent years, plasma biomedicine has attracted increasing attention as a promising method of sterilization and other biomedical applications. This research aims to develop and characterize an argon-based non-thermal atmospheric-pressure plasma jet (APPJ) with an application of sterilization and nail disease treatment. We characterized the electric properties by an electrical measurement system and quantified the active species in APPJ by optical emission spectroscopy (OES). The gas temperature of plasma jet is below 37 °C, which is generally free of thermal damage for the human body. The results of OES measurement indicate that this APPJ has a high intensity of hydroxyl radicals (OH*), which has shown promise in killing microorganisms. The preliminary result from inactivation experiments also show that APPJ efficiently kills bacteria (P. aeruginosa) and yeast (C. albicans). Furthermore, we used bovine hoof as a surrogate model for human nails for penetration tests. The results demonstrated that argon APPJ is good in inhibition of P. aeruginosa (90% in 5 min) and C. albicans (76% in 5 min) on agar plates. In addition, antimicrobial tests showed that approximately 2-log and 4-log reduction can be reached for P. aeruginosa and C. albicans in 5 min, respectively, when the argon APPJ was applied with them deposited at the back of the bovine hoof. We attribute the latter which contradicts with the former may be caused by many possible factors, which include the biofilm formation of the P. aeruginosa on the bovine hoof, the nature and the size difference of these two pathogens.

Characterization and performance of coupled atmospheric pressure argon plasma jet with n-hexane electrospray for hydrophobic layer coatings on cotton textile

In this study, we developed an apparatus by combining n-hexane electrospray and atmospheric pressure argon plasma jet for deposition diamond like carbon (DLC) layer as a hydrophobic film on cotton textile. n-Hexane was used as a hydrocarbon precursor for preparing ionized spray for atmospheric pressure plasma (APP) jet. In order to characterize the plasma, electrical measurement and optical emission spectroscopy (OES) were employed. The electron excitation temperature of the APP was estimated by Boltzmann plot method. Water contact angle (WCA) measurement was used to evaluate the hydrophobicity of the samples. The results showed that the water contact angle of these samples increases after treating by a combination of n-hexane electrospray and the APP jet. Considerations of aging effect on the samples clarified that the samples coated with longer times show better withstand against aging effect. Washing durability investigation of the samples showed that the hydrophobic property of the samples has acceptable durability in 50 washing cycles. Formation of diamond like carbon (DLC) coating on the substrates was proved by Raman and X-ray photoelectron spectroscopy (XPS) then characterized by FE-SEM analysis, energy dispersive spectroscopy (EDX) and X-Map probe. The results of this work were compared to the original one whose liquid precursor was ethanol. It was concluded that n-hexane precursor could result in better hydrophobicity comparing with that of ethanol precursor.

Wound Healing in Streptozotocin-Induced Diabetic Rats Using Atmospheric-Pressure Argon Plasma Jet

In this study, we used an argon-based round atmospheric-pressure plasma jet (APPJ) for enhancing wound healing in streptozotocin (STZ) induced diabetic rats. The APPJ was characterized by optical emission spectroscopy. We induced Type 1 and Type 2 diabetes in rats with different amounts of STZ combined with normal and high-fat diets, respectively. The wound area ratio of all the plasma-treated normal and diabetic groups was greatly reduced (up to 30%) compared with that of the untreated groups during healing. Histological analysis revealed faster re-epithelialization, collagen deposition, less inflammation, and a complete skin structure in the plasma-treated groups was found as compared with the untreated control groups. In addition, the new blood vessels of plasma-treated tissues decreased more than untreated tissues in the middle (Day 14) and late (Day 21) stages of wound healing. The plasma-treated wounds demonstrated more transforming growth factor beta (TGF-β) expression in the early stage (Day 7), whereas they decreased in the middle and late stages of wound healing. The levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) increased after plasma treatment. In addition, plasma-treated water had a higher concentration of hydrogen peroxide, nitrite and nitrate when the plasma treatment time was longer. In summary, the proposed argon APPJ based on the current study could be a potential tool for treating diabetic wounds.

Laminar and turbulent flow modes of cold atmospheric pressure argon plasma jet

Laminar and turbulent flow modes of a cold atmospheric pressure argon plasma jet are investigated in this work. The effects of the gas flow rate, applied voltage, and frequency on each plasma mode and on intermodal transitions are characterized using photographic, electrical, and spectroscopic techniques. Increasing the gas flow rate increases the plasma jet length in the laminar mode. Upon transition to the turbulent mode, increasing the gas flow rate leads to a decrease in the plasma jet length. The flow rate at which the jet transitions from laminar to turbulent increases with the applied voltage. The presence of nitric oxide (NO) radicals is indicated by the emission spectra of the turbulent plasmas only, while excited Ar, N2, OH, and O excited species are produced in both laminar and turbulent modes. With no distinctive behavior observed upon transition between the two operating modes, the power consumption was found to be insensitive to gas flow rate variation, while the energy density was found to decrease exponentially with the gas flow rate. Rotational and vibrational temperature measurements of the two plasma modes indicated that they are of the non-thermal equilibrium plasma type. Since they offer NO radicals while maintaining the benefits of the laminar plasma jet, the turbulent plasma jet is more useful than its laminar counterpart in biomedical applications.

Confluence or independence of microwave plasma bullets in atmospheric argon plasma jet plumes

Plasma bullet is the formation and propagation of a guided ionization wave (streamer), normally generated in atmospheric pressure plasma jet (APPJ). In most cases, only an ionization front produces in a dielectric tube. The present study shows that two or three ionization fronts can be generated in a single quartz tube by using a microwave coaxial resonator. The argon APPJ plumes with a maximum length of 170 mm can be driven by continuous microwaves or microwave pulses. When the input power is higher than 90 W, two or three ionization fronts propagate independently at first; thereafter, they confluence to form a central plasma jet plume. On the other hand, the plasma bullets move independently as the lower input power is applied. For pulsed microwave discharges, the discharge images captured by a fast camera show the ionization process in detail. Another interesting finding is that the strongest lightening plasma jet plumes always appear at the shrinking phase. Both the discharge images and electromagnetic simulations suggest that the confluence or independent propagation of plasma bullets is resonantly excited by the local enhanced electric fields, in terms of wave modes of traveling surface plasmon polaritons.

Physical Plasma Elicits Immunogenic Cancer Cell Death and Mitochondrial Singlet Oxygen

Plasma oncotherapy receives increasing attention due to considerable success in preclinical research. Different plasma sources were shown to induce cancer cell death in vitro and in vivo . Plasmas for medicine expel reactive species of many kinds. These have been implicated in the induction of immunogenic cancer cell death that increases the visibility of killed cells to the immune system. Cell membrane-bound calreticulin (CRT) serves as key damage-associated molecular pattern molecule to elicit antitumor immune responses. To investigate CRT translocation upon challenge with medical plasma, CT26 colon cancer cells were treated in vitro using the atmospheric pressure argon plasma jet kINPen. Cells underwent apoptosis, which was accompanied by exposure of CRT. Interestingly, CRT was upregulated on viable as well as dead cells, and remained upregulated up to 72 h post-treatment. Cell death was preceded by loss of membrane potential in mitochondria. These endosymbionts are capable of generating singlet oxygen, a molecule that has been suggested to drive radical chains in plasma cancer cell death. Using fluorescent probes, we identified a role of endogenous (mitochondrial-derived) over exogenous (plasma-derived) singlet oxygen in plasma-treated cancer cells.

The feed gas composition determines the degree of physical plasma-induced platelet activation for blood coagulation

Cold atmospheric (physical) plasma has long been suggested to be a useful tool for blood coagulation. However, the clinical applicability of this approach has not been addressed sufficiently. We have previously demonstrated the ability of a clinically accepted atmospheric pressure argon plasma jet (kINPen® MED) to coagulate liver incisions in mice with similar performance compared to the gold standard electrocauterization. We could show that plasma-mediated blood coagulation was dependent on platelet activation. In the present work, we extended on this by investigating kINPen®-mediated platelet activation in anticoagulated human donor blood ex vivo. With focus on establishing high-throughput, multi-parametric platelet activation assays and performing argon feed gas parameter studies we achieved the following results: (i) plasma activated platelets in heparinized but not in EDTA-anticoagulated blood; (ii) plasma decreased total platelet counts but increased numbers of microparticles; (iii) plasma elevated the expression of several surface activation markers on platelets (CD62P, CD63, CD69, and CD41/61); (iv) in platelet activation, wet and dry argon plasma outperformed feed gas admixtures with oxygen and/or nitrogen; (v) plasma-mediated platelet activation was accompanied by platelet aggregation. Platelet aggregation is a necessary requirement for blood clot formation. These findings are important to further elucidate molecular details and clinical feasibility of cold physical plasma-mediated blood coagulation.

Cold Physical Plasma Does Not Promote Metastasis-Like Spread In Human Pancreatic Cancer Cell Lines

1. Purpose/Background Up to 76% of pancreatic resections show histologically positive resection margins leaving patients with residual tumor load after surgery. Cold Physical Plasma (CPP) has shown antitumor effects inducing apoptosis. The application of CPP after resection of pancreatic cancer could significantly decrease the local microscopic tumor load. Yet, it is unknown whether plasmas may support tumor metastasis. Hence, the aim of this study was to characterize the influence of CPP on possible tumor cell spread. The cell adhesion profile of four different human pancreatic cancer cell lines was analyzed. In addition, the effects of CPP on Epithelial-to-Mesenchymal-Transition (EMT) of pancreatic cancer cells were investigated, especially the relation between ZEB-1 and E-Cadherin. To complete the in-vitro studies, the chicken chorioallantoic membrane model was used as an in-vivo model. In relation to preliminary experiments, the cell adhesion molecules as well as the tumor cell spread were characterized for each cell line. 2. Methods Using flow cytometry, the pancreatic cancer cell lines PA-TU-8988-T, PA-TU-8988-S, MIA-PaCa-2, PANC-1 were analyzed for CD324 (E-Cadherin), CD326 (EpCam), CD49b (Integrin α-2) and CD49d (Integrin α-4) as well as ZEB-1 after 60sec of CPP treatment. Furthermore, metabolic activity was investigated. All experiments were carried out in a 96-well plate in which adherent cells and supernatants (possibly containing floating cells) were observed. CPP treatment was performed employing the atmospheric pressure argon plasma jet kINPen 11. Examining the mechanic influence of the gas flow was done employing argon gas treatment without plasma. 3. Results/Conclusion CPP reduced viability and metastasis potential of aggressive pancreatic carcinoma cell lines, whereas less aggressive cell lines were less affected. PATU-T showed significantly decreased viability after 60s of CPP treatment compared to controls (p= 0.0304), whereas PATU-S was less affected (p=0.3372). CPP-treatment increased the expression of E-Cadherin (p=0.0001) in PATU-T and MIA-PaCa-2 (p=0.0001) compared to untreated controls. This might affect potential metastasis in these cell lines whereas PATU-S and PANC-1 were not significantly affected. Analyzing the number of viable cells after 4 days (as offspring of detached but viable floating tumor after plasma treatment) in all four cell lines, no changes between treated and non-treated cells were observed (p=0.8478). These results confirm the antitumor effect of Cold Physical Plasma in pancreatic cancer. Furthermore, the results are promising, that CPP is a safe treatment option which may reduce local reoccurrence and moreover has no promoting effects on tumor cell spread.

Cold plasma treatment of in vitro gliomas and patient-derived tumors – Role of human myeloid cells

Tumor-associated macrophages (TAM) are the pre-dominant myeloid cells within malignant glioma and are a poor prognostic factor in patients. TAM in malignant glioma show a tumor-supporting, so-called M2 phenotype. The aim of this study was to characterize phenotype and relevant markers of monocytes/macrophages in the tumor microenvironment following exposure to cold physical plasma Monocytes were enriched from peripheral blood mononuclear cells derived from young healthy volunteers donating blood after informed consent and in accordance with the guidelines of the local ethics committee. Monocytes were co-cultured with a glioma cell line (U87MG). The latter readily induced a M2 phenotype in these monocytes as seen by an increase in CD163 expression. Prior to co-culture, either U87MG cells or monocytes were treated with an atmospheric pressure argon plasma jet (kINPen) for 15 seconds or 5 seconds, respectively. Non-treated co-cultures as well as single monocytes cultures served as controls. FACS immuno-phenotyping of monocytes/macrophages was performed for CD55, CD97, CD162, CD163, CD169, CD204, CD276, HLA-DR, and HLA-ABC after 24h, 48h, and 72h. M2 polarization of monocytes by U87MG was neither attenuated nor reversed by plasma treatment. We next exposed primary glioblastoma patient material to cold physical plasma (kINPen) ex vivo. After treatment, tissues were incubated for 24h, and supernatants were collected. Multiplex cytokine analysis of supernatants. Results of five patients showed an absence of IFNα, IFNγ, IL12p70, IL17α, and IL23, and a presence of IL1β, TNFα, MCP1, IL6, IL8, IL10, IL18, and IL33 in samples. A mixed response was observed. For instance, both of the myeloid-cell interacting proteins MCP1 and IL1β are associated with glioma aggressiveness, and secretion of IL1β decreased after plasma treatment whereas MCP1 was increased. Glioma tissue sections will determine the distribution of myeloid cells within the tumor after plasma treatment compared to controls. Download : Download high-res image (136KB) Download : Download full-size image Figure 1: Fold change of several chemokines/cytokines in kINPen plasma-treated primary human glioblastoma samples compared to untreated glioma tissue.

Where Do Ros Go? Oxidation Cascades In Melanoma Exposed To Cold Physical Plasma

In plasma medicine, physical atmospheric cold plasma is used for application in therapeutic appliances such as wound healing or decontamination of infected skin.[1] Over the last decade, plasmas became a valuable research tool for cancer therapy.[2] Many groups have not only reported an efficient killing of cancer cells with plasma but also a selectivity of the killing of malignant over non-malignant cells.[3] Yet, following the trajectories of plasma-derived reactive oxygen and nitrogen species has only begun to be explored. First modeling studies suggest an important role of lipid peroxidation and phosphatidylserine content in the cell membrane.[4] Using fluorescent reporter dyes, many groups have reported cytosolic oxidation following plasma treatment. Some groups claim that DNA double-stranded breaks are a direct product of reactive species deposition by plasmas.[5] Using human melanoma cells, the purpose of this work was to study in detail how different cell compartments are affected reactive species derived the atmospheric pressure argon plasma jet kINPen. Using confocal laser scanning microscopy, several versions of fluorescent reporter dyes were used to assess oxidation qualitatively and quantitatively. We hope our study to contribute to the understanding how plasma-generated reactive species penetrate cells and affect their behavior and viability, especially for future plasma cancer treatment.